I can only see the picture on the first page, the other ones arent coming through like the first one but to me the first one looks fine. They have purple stems sometimes. Id be running a calmag supplement at one drop a litre but thats just how i do. I dont think 7-800 would be unreasonable for that plant. Id just keep er goin. Your waters really high ph out of the tap so its understandable why it wants to go back to being 7.8 again. I get flack for this all the time but i never use ph down. Ive run with water starting ph 8 and it drifts up to 9.5 in two weeks and the plant is huge and healthy. Like for me id let it go to 8.8 in your circumstance and then change the rez and just hope it took two weeks to get there. If i couldnt do that id switch to coco or dirt if i was moving ph points a day at a time and had to keep feeding ph down. So the only problem is the purple stems, and you said crispy leaves? Your not foliar spraying anything are you?